FIG. 1 shows an off-grid energy storage system, which includes multiple energy storage inverters, a direct current side of each of the energy storage inverters is connected to an independent storage battery, and alternate current sides of the energy storage inverters are connected in parallel with the same alternate current bus, thereby converting multiple direct current inputs into one alternate current output.
Ensuring consistency of operating states of the storage batteries in the off-grid energy storage system, for example, ensuring balance among the states of charge (SOC) of the storage batteries and ensuring balance among voltages across the storage batteries is an important mean for ensuring safe and stable operation of the off-grid energy storage system. However, the current technical force still cannot provide technical support for maintaining the balance among the SOCs of the storage batteries or maintaining the balance among voltages across the storage batteries.